Inner Focus is a priest ability learned at level 36 for those with the Discipline specialization. It reduces the mana cost of a trio of healing spells, as well as increasing their critical strike effect by 100%.

Patch 4.0.6 (8-Feb-2011): Strength of Soul now occurs when the priest casts Inner Focus on oneself, rather than Power Word: Shield. In addition, Strength of Soul now also causes the priest to become immune to silence, interrupt, and dispel effects for 2/4 seconds after using Inner Focus.